So years ago when my Surefire 6p was brand new (to me) a colleague borrowed it. He was having problems filling the tank on his truck as there was some metal protective sheets in the way and whilst we chatting it suddenly went dark followed by a deep 'clunk' and him swearing.
He wondered off to get the long neck tool extraction thingy from the workshop and after getting it out I held onto it as well as the metal plates so he could carry on filling the 500 litre diesel tank.
Once done we found some suitable cleaning solutions and used that, but I didn't switch it off as I wasn't sure how watertight it was, so left it on. It soon flattened the CR123 in it and he grabbed me one from his truck, as they were used on one of the remote control panels.
It did create a nice glow in the fuel tank while it was in there
When I next saw him in the yard some months later he had had a 24v work lamp set up near the tank and some straps to hold the sheeting up so he could see what he was doing.
Torch survived, still in use today. Took ages to get that diesel smell out though